Chernobyl, Ukraine
On 26 April 1986, following an explosion at the Chernobyl Nuclear power plant, a cloud of radioactive dust exhausted from the severely damaged Reactor No.4.The Soviet government, for some reason, refused to admit the accident, not only to the rest of the world, but to the city of Pripyat (pop. 11,000) located only 3 kms away, directly under the toxic cloud. It was only when the Swedish government alerted the world to the incident 4 days later that the evacuation commenced.